How big do you feel

Hack Details: People often perceive themselves as bigger, shorter, fatter or skinnier than they really are. But how accurate are people at judging their people shape and how as a result their BMI.

What you need to make it happen?: Iv got the idea and an experiment lined up in the near future. What I need is a coder to design a Avatar which changes shape according to 2 linear sliders (height and weight) which are linked to the BMI formula. I also need the function for BMI to be guessed by participant and actual BMI to be ouptut